Material storage and dispensing vessels are used in a wide variety of industrial processes and commercial and personal applications. Various types of liquids and gases may be placed into vessels such as storage cylinders for transport and ultimately dispensation. One desirable industrial field for application of material storage and dispensing vessels is the fabrication of semiconductor devices.
In the fabrication of semiconductor devices, materials of various types and purposes are deposited on semiconductor substrates typically comprising monocrystalline material such as silicon dioxide. Deposited materials may include copper, aluminum, and other metals to form metal lines or other circuit features within trenches of the semiconductor substrate. Additional circuit features and material layers may be formed on the semiconductor substrate throughout the fabrication process.
In order to form trenches as described above, a photoresist material is first deposited above the semiconductor substrate. The manner of transport and delivery of photoresist material to the semiconductor substrate may be critical to the fabrication process. For example, the cost of applying a wrong type of photoresist may be quite extreme in terms of destroyed high-value semiconductor substrate, wasted high-purity chemicals, and manufacturing process interruption required to correct such an error. Despite this fact, photoresist material supply chains are usually managed with manual systems having intrinsic inefficiencies and a high risk for error, as the typical supply chain involves multiple parties each having independent material tracking platforms incapable of communicating with one another.
The photoresist material described above is typically transported and delivered to the surface of the semiconductor substrate in a liquid form. Spin-on processes are commonly used to apply and spread a thin coating of photoresist across the semiconductor substrate surface. Parameters of the spin-on process are selected to ensure an extremely uniform, thin distribution of the photoresist across the surface of the semiconductor substrate. The material application step is typically followed by a step of heating the semiconductor substrate to solidify the photoresist layer.
The solid photoresist layer described above may be patterned to allow for the formation of trenches therebelow by conventional etching techniques. However, proper trench formation and uniformity thereof is dependent in part upon the uniformity of the thin photoresist layer defining the trenches. Indeed, proper transport and delivery of photoresist material to the semiconductor substrate is critical to the fabrication of a reliable semiconductor device. In fact, as device features such as metal lines become smaller and smaller with advanced semiconductor wafer designs and processing technologies, the adverse effects of photoresist non-uniformity on a device feature are magnified.
Achieving a uniformly thin photoresist layer may require application of a spin-on or other process that employs parameters based on the particular physical and functional characteristics of the photoresist material. Unfortunately, characteristics of a photoresist material type may vary from one batch to the next, or as a result of environmental or time factors inherent in the transport and storage of these materials from the point of origin to the point of use. For example, photoresist viscosity may vary from one batch or vessel to the next, and photoresist properties can be degraded with environmental conditions (e.g., high temperature) and/or age. In view of the variation between different batches and/or vessels or photoresist, it may be extremely difficult to establish predetermined fixed parameters for forming an adequately uniform photoresist layer on a semiconductor substrate. Thus, proper transport and application of photoresist material to the semiconductor substrate includes challenges relating not only to providing the proper type of photoresist material, but also to employing application parameters appropriate to the precise characteristics of the specific photoresist material provided. Sampling and individualized testing of the contents of each vessel immediately prior to end use is impractical in production facilities, and particularly in high-cost production lines intended for high-throughput operation. Moreover, owing to the limited shelf life of photoresist, limited storage capabilities, and the time typically required to perform material analyses, it can be inefficient for a material (e.g., chemical) supplier to store whole batches of materials prior to customer shipment while waiting for results of material analyses.
While challenges associated with the use of photoresist materials have been described hereinabove, similar or analogous difficulties exist in connection with many classes of materials used in semiconductor fabrication and in various other industrial processes. Accordingly, the present invention is not limited in application to photoresist or semiconductor materials. Limitations associated with handling materials of various types include the relative difficulty of managing a large number of vessels having different contents. For example, in a manufacturing process utilizing various chemical reagents or precursor materials stored in vessels of similar types, it may be difficult to perform any of the following tasks: ensure that process parameters appropriate to the specific material disposed in a specific vessel are used in every instance; prevent supply chain interruption; prevent overstock of materials; utilize materials received first-in-time while avoiding the use of degraded or unduly old (‘expired’) materials; track material-containing vessels already released to customers for potential safety or quality recalls; comply with regulatory storage and/or discharge limits, and comply with regulatory discharge limits. Tracking of vessel movement not only into a material ingress (receiving) area, but also among various functional areas in a material end use process facility would be particularly desirable to aid in identifying and retrieving materials determined to have emanated from contaminated production lots or batches, and/or to aid in supply chain management. It would be desirable to provide systems and methods to address these and other concerns. Traditional material management tools (e.g., bar code systems) are not well-suited to addressing such concerns since they lack dynamic update capability, require line-of-sight scanning, rely on other manual actions, and are usually limited to providing vessel identification information.
To improve the functions of material handling and utilization, enhance process performance and analysis, and reduce material storage vessel misconnect errors, it would be desirable to automate the supply of information from a material storage vessel to a material-consuming process tool. Such automation would preferably address not only communication hardware and related interfaces, but also communication modes and protocols, and data formats and specific data content.
In sensitive and chemical-intensive processes such as semiconductor manufacture, it would be desirable to correlate a fabricated product with information about materials used in its manufacture. Such correlation would be highly useful for process optimization and ongoing quality assurance and quality control. For example, product defects or performance problems attributable to particular source materials—whether or not within material specifications—may not be detected until the fabricated products are rigorously tested. The ability to correlate device performance to source materials would facilitate process optimization and improvement of material specifications without necessarily requiring universal quality assurance testing of all products. To date, however, such benefits have not been realized because product information has not been uniformly and reliably correlated to information regarding materials used in product manufacture.
The foregoing background discussion demonstrates the need for improved material management systems and methods.